By Alice McFarlane

Longer rotation key to keeping a handle on clubroot

Dec 8, 2020 | 4:24 PM

MELFORT, Sask. – A three-year canola rotation can help keep clubroot spore numbers under control while a four-year rotation can reduce clubroot spore populations even more but the benefits begin to decline.

That word from University of Alberta professor of plant pathology Dr. Stephen Strelkov, a leading expert on clubroot in canola.

Strelkov spoke at the virtual Agronomy Research Update organized by the Saskatchewan Ministry of Agriculture.

He said seed varieties with second generation clubroot resistance are effective against new disease pathotypes, but he warned it is not a silver bullet.

“If you think about tadpoles, initially you have many and then most will die in a short time. A few will live a long time,” Strelkov said. “That’s the thing with resting spores. Most die fairly quickly, let’s say two or three years after the crop has been grown. But there is a subset that can last 15 or 20 years. Those are the ones that cause problems.”

NDTR

First Nations, Inuit and Metis leaders say work lays ahead on road to reconciliation

17h ago

Tapestrama Tension

Russia-Ukraine war dividing local cultural connections

Sep 29, 2024

Raiders lose 5-4

Second period woes plague Raiders against Broncos

Sep 29, 2024

Strelkov said certain seed companies are promoting third generation clubroot resistance. He said he doesn’t know what the basis of that resistance is.

“Presumably, they have something different that they’re making the claim of third generation. But it is very difficult to say. We’re not that clear what is present in second generation resistance. We suspect it’s not the same across varieties. You would have to ask those suppliers why they are making that claim,” he said.

Manitoba is showing a wider variety of clubroot pathotypes. Strelkov said that trend is alarming.

“Why are we seeing so much diversity there? Is there more potential if clubroot becomes more prevalent in Manitoba that we’re going to have more of these new strains that break resistance?” Strelkov said. “We don’t know for sure yet but to me it’s a little bit concerning.”

Strelkov said it doesn’t bode well for the future if the disease becomes more and more severe.

–

alice.mcfarlane@jpbg.ca

On Twitter: @AliceMcF